The present invention relates to eccentric gear mechanisms, and methods of transferring turning forces thereby.
Eccentric gear mechanisms are known in the art. An eccentric gear mechanism is known which includes an inner ring gear with outer gear teeth provided on its outer circumference, an outer ring gear with inner gear teeth provided on its inner circumference and engaging with the outer gear teeth of the inner ring gear, and means for generating an eccentric movement between the gears.
The known eccentric gear mechanisms usually have some disadvantages. In particular, they create unwanted vibrations at high speed. The known eccentric gear mechanism turns an inner ring gear, which moves against the outer, centrally located ring gear, so that the outer ring gear turns in the same direction as the eccentric sun drive and the inner ring gear in the opposite direction unlike planet gears. This means that action and reaction are reversed. While this is not a problem with a tool having just a single eccentric gear mechanism as the direction of the input drive can be switched, it is a problem when two or more eccentric gear mechanisms are placed on top of each other or one eccentric gear mechanism is placed on top of planetary gear stages to obtain a high ratio, because unlike the planetary gear mechanism, the eccentric gear mechanism can not use in its outer, centrally located ring gear as the reaction absorbing part, because it would decrease the total ratio by the ratio of the eccentric gear mechanism. It is known that sliding motion is roughly ten times higher than turning friction, and if anything moving eccentric needs to transmit a central force until now the sliding motion was required in the existing eccentric gear mechanisms.
It is therefore believed that the existing gear mechanisms can be further improved.